This relates to reference beam generators of the type used to project plumb, level, and square reference beams of visible light on walls, ceilings or floors to facilitate spatial positioning at a construction site or elsewhere. Such tools have been used to provide visible reference lines for construction layout of walls, beams, joists, ceilings, laying tiles, hanging shelves and cabinets, and for a many other similar activities.
Prior art reference beam generators have typically produced only one or two reference beams in specific geometric configurations. While useful, such devices have limited application. Additionally, commonly such devices provide stationary reference beams, or rotating beams. Stationary reference beams are of limited use. Devices which produce rotating reference beams, provide the ability to produce a line across a surface. However, in order for the line to be visible, a somewhat higher power light source, typically a laser, is required because the power of the rotating beam is spread over the entire 360 degree rotation of the beam. A relatively short length of the beam path across a wall or other surface might only receive one-tenth of the beam's power, for example, if it amounts to only one-tenth of a rotation of the beam. Therefore, a higher power laser light source must necessarily be included in the device. Not only does this reduce battery life, but it also raises safety concerns. Should the beam stop rotating, then the power of the beam directed at a stationary point must somehow be reduced, or the laser must be switched off immediately.
It is seen that there is a need for a reference beam generator which provides maximum flexibility in its use, provides multiple reference beams, and permits adequate operation with lower power consumption and lower beam power levels.